基于多物理场耦合的U3Si2燃料与双层SiC包壳组合的轻水堆燃料性能分析

基于COMSOL平台开发了一套基于多物理场全耦合的燃料性能分析程序，并通过径向功率分布模型对比验证了该程序的正确性与准确性；然后进一步分析了U₃Si₂燃料与双层SiC包壳组合、U₃Si₂燃料与锆合金包壳组合在反应堆正常运行工况下的性能，并与UO₂燃料与锆合金的组合进行了对比分析。计算结果发现U₃Si₂燃料与锆合金包壳组合相比UO₂燃料与锆合金的组合具有更低的燃料中心温度、裂变气体释放量及内压，但气隙闭合时间会提前；而U₃Si₂燃料与双层SiC包壳的组合相比U₃Si₂燃料与锆合金的组合具有更高的燃料中心温度、更大的裂变气体释放量及内压，且随着燃耗的增加，其燃料中心温度大幅增加，与锆合金包壳相比，双层SiC包壳能够有效延迟气隙闭合，缓解燃料与包壳的力学相互作用。 

Fuel Performance Analysis of Light Water Reactor Based on the Combination of U_3Si_2 Fuel and Two-Layer SiC Cladding Based on Multi-Physical Field Coupling

Based on COMSOL platform, a fuel performance analysis program based on multi-physical field full coupling is developed, and the correctness and accuracy of the program are verified by comparing with the radial power distribution model; Then the performances of the combinations of U₃Si₂ fuel and two-layer SiC cladding, U₃Si₂ fuel and zirconium alloy cladding under normal reactor operating conditions are further analyzed and compared with the combination of UO₂ fuel and zirconium alloy. The calculation results show that the combination of U₃Si₂ fuel and zirconium alloy cladding has lower fuel center temperature, fission gas release and internal pressure than that of UO₂ fuel and zirconium alloy, but the air gap closing time will be earlier; The combination of U₃Si₂ fuel and two-layer SiC cladding has higher fuel center temperature, greater fission gas release and internal pressure than the combination of U₃Si₂ fuel and zirconium alloy, and its fuel center temperature increases significantly with the increase of burnup. Compared with zirconium alloy cladding, two-layer SiC cladding can effectively delay the closing of air gap and alleviate the mechanical interaction between fuel and cladding.